1. Field of the Invention
This invention relates generally to vapor recovery and more specifically, vapor recovery in oil and gas well production equipment.
2. Description of the Related Art
In typical oil and gas well production operations, oil moves from wells through a system of high pressure lines to a holding tank where it is then transferred to a refinery to be used in other applications, for example to power combustion engines. The gas produced in this operation moves through the high-pressure lines, is separated from the oil and then is directed into a sales line where it is distributed to natural gas customers. In separating the oil and gas through this high pressure system, often a small amount of the gas is moved into the holding tank instead of the sales line. Additionally, gas can be produced in the holding tank due to evaporation in the tank. While it is necessary to have some gas in the holding tank to prevent a fire due to the presence of air, too much gas in the holding tank is a problem due to the potential for the tank to rupture.
Currently, when there is too much gas in the holding tank, the gas is released into the atmosphere through a release valve on the top of the tank. For many years the release of this gas into the atmosphere did not appear to be a problem. However, in recent years concerns over air quality and ozone depletion have pressured the industry to make a change to the method of release. The Environmental Protection Agency (EPA) has set mandatory guidelines for the amount of gas that can be released from the holding tank into the atmosphere. Other than burning the gas, there is currently no technology on the market for reducing the amount of gas released from the holding tank into the atmosphere. This is wasteful, because the released gas could be sold to produce useful energy.
Therefore, it is the object and feature of the invention to provide a method and apparatus for reducing the amount of gas being released into the atmosphere from the holding tank during operation of oil and gas well production.